1. Field of the Invention
The present invention relates to a data dictionary directory system having a function to register and control definition information that specifies the structure of data base of a data base system and to convert it into an execution time format.
2. Description of the Prior Art
When a definition information is to be registered being divided into several definition units in a data dictionary directory system, it is accepted practice to confirm whether there is non-coordination in the definition content among the definition units.
The dictionary directory has been described in the Computing Surveys, "The Integrated Dictionary/Directory System", Vol. 14, No. 2, published by ACM, June, 1982.
In the dictionary have been stored definition information called logic schema which specifies the structure of the whole data base and definition information called sub-schema which specifies the structure of the data base of a range in which a user program can be used for each of the user programs, the definition information being stored in a source form that is adapted to registering and controlling the definition information.
The directory is converted into the form of a table so that definition information stored in the dictionary can be easily utilized for executing the access processing into the data base.
The registration unit (definition unit) of definition information onto the dictionary is set in a variety of sizes depending upon the characteristics of the structure of data base that is to be defined so that it can be suitably utilized by a user, and the generation unit of the directory table is set by taking into consideration the execution time performance such as data base control program and the independence among the definition units used for generating tables. Usually, the definition unit is different from the generation unit of table.
The definition information registered into the dictionary is used not only for generating a directory but also for a variety of uses such as for confirming that the data base system access instruction in the user program is not contradictory to the definition content of the data base system when the user program is being compiled.
In order to confirm the coordination of definition content among the definition units, the definition information related to the dictionary and the directory must have been stored.
In the conventional system in which the above-mentioned confirmation is carried out when the definition information is to be registered, it is essential that the related definition information is all prepared at the time of registration. Therefore, sequence (e.g., definition information of lower bits is registered after related definition information of upper bits is registered) is required for registering the definition unit, with no flexibility in the work of registration and control.